2, 4-diamino-5, 6-dialkylpyrido (2, 3-d) pyrimidines and method



A f v c vi Unit d S ates. atfltnhcc 2,4-DIAMINO-5,6-DIALKYLPYRIDO 2,341 PYRIMIDINES AND METHOD George H. Hitchings, Yonkers, and Kurt WQLedig, New

Rochelle, N.Y., assignors to Burroughs Wellcome & Co. .(U.S.A-.)-Inc., Tuckahoe, N.Y., a corporation of New York a No Drawing. Application May- 1, 1958 Serial o. 732,126

5 Claims. cl. zen-256.4

N I 'M wherein R and R are selected from the group consisting of lower alkyl-radicals providing that together they may represent one of the divalent, trimethylene 'and tetramethylene radicals. The new substances are considerably more potent than the group of pyrido(2,3-d)pyrimidines of the copending application'US. Serial No; 707,854. In I the previous work it was possible to prepare 5,7- and 6,7- 'disubstituted derivatives but the 5, 6-dialkyl derivatives were unattainable by the method used. The invention, accordingly, contemplates a novel method for the preparation of derivatives of the indicated formula.

That the newiderivatives are of considerably greater importance is attested by their superior activities as compared with the related derivatives as shown by the following representative tests:

INHIBITORY EFFECTS OF PYRIDO(2,3 d)l YRlMI- DINES oN BACTERIA v 7 Many applications of the abovefindings will hea parent to those skilled in the art. The substances may be used topically inlotions and ointmentsrin concentra-.

' tions of 0.l-to1 percent to inhibit bacterial growth: In addition they potentiate'rthe sulfonamides and so ma'y be used in combination with the latter to enhance theirie ifiectiveness. H [Q --The new'substances are prepared by a -new route; 2,4,6-triaminopyrimidine reacts with a suitable jacylace l at'ented May 17, 1960 2' tate to form a 2,4-diamino-5,6-dialkyl-7-hydroxypyrido- (2,3-d) pyrimidine. This is converted successively to the 7-chloro and 7-mercapto derivative then to the desired 7-unsubstituted derivative. These reactions are illustrated 5 be1ow:

N r H: 1

c0 l p +i HR2 I 2 Y 10 HgN-KN NH: (i1 0202 5 NHrL N N/ O H NH i ' N N V N/ The teachings of this application are illustrated in the following examples; the scope, however, is defined in the claims.

' PYRIDO (2,3-(1) PYRIMIDINES Example I 2,4 diamino-7-hydroxy 5-methyl-d-propylpyrido (2,3-d) pyrimidine Thirty grams of 2,4,6-triaminopyrimidine was heated with 100 ml. of ethyl-n-propylacetoacetate in an oil bath kept at 240-250 and the low-boiling fraction was 'dis- 1 tilled off during the reaction, over a period of minutes. Finally, the reaction mixture was subjected to vacuum distillation to remove the excess ester. The c'ooledresidue was ground up with methyl alcohol, filtered, leached with water and refiltered;

Twenty-five grams of the crude product was refluxed with 1 liter acetic acid-H00 ml. acetic anhydride for 4 hours followed by complete evaporation of the solvent. The monoacetyl derivative was refluxed with 300ml. of

phosphorus oxychloride for 0.75 hour and evaporated to a small volume. The mixture was poured over ice, neutralized with ammonium hydroxide and the precipitate of 2,4 diamino-5-methyl-6-propyl-7-chloropyrido(2,3-d)

pyrimidine was filtered. 1

The wet cake was heated with 200 ml. of 2 N NaSH overnight at 140 in a steel bomb. The resulting precipitate; of 2,4-diamino-S-methyl-6-propyl-7-mecaptopyrido- 45 (2,3-d) pyrimidine was filtered and washed with water.

' .Ten, gramsof the crude 7-mercapto compound was heated under reflux conditions in"1 liter alcohol,

with ml. of ammonium hydroxide and 50 g. of Raney nickel catalyst for 12 hours. After addition of a further "50 g. of Raney nickel refluxing was continued for another 12 hours to complete the reaction. The filtrate was evaporated on the steam bath and the residue dissolved in 100 ml; of water with the addition of 2N. HCl, filtered andthe clear vfiltrate made alkaline with sodium hydroxide. The resulting" 2,4-diamino-5-methyl-6-propylpyridoj (2,3-d )pyrimidine was recrystallized from"70% alcohol.

. Its ultraviolet absorption spectrum showed a maxima at'320 and 3 30 (inflection) my. at pH 1 and 341 and 350- 60 370 (inflection) mu at pH 11.;

v Example2i 2,4 diamino-5 methylpyrido(2,3?11) 1 pyrimidine 1 Twenty-five grams of 2,4,6-triaminopyrimidine re- 7 mixture wasffcooledand 'the'precipitate collected. I

The crude product was refluxed in 750 ml. acetic acid .in the presenceof lQQmLof acetic anhydride for 4 hours.

7 after eiapcratii lgto'dryness thefacetylated 2,4-diamino- 5'-methyl-7'-hydroxypyrido(2,3-d)pyrimidine was refluxed enemas with 200 m1. of phosphorus oxychloride for 3 hours. The reaction mixture was evaporated, and the residue was diluted with chloroform followed by neutralization with gaseous ammonia. The vreaction mixture was filtered from inorganic material and the. filtrate evaporated, to; dryness. Ten gramsof the 7 96111010 product was treated with 150 ml. of'2 'N NaSH at 145.in .a steel'bomb for 14 hours. The reaction mixture was filtered and the precipitate washed with water. The 2,4-diamino--methyl-7- mercapto compound was filtered and reprecipitated from dilute sodium hydroxide solution by the addition of acetic acid.

Two grams of the 7=mercapto derivative was refluxed with 250 of 95% alcohol, 50ml. of concentrated ammonium hydroxide and about 5 g. of Raney nickel for 6 hours. After this time. another portion of 5 g. of Raney nickel catalyst and a few ml. of ammonium hydroxide were added and the refluxing Was continued overnight. The reaction mixture was filtered'to remove the Raney nickel which was washed with 95% alcoholand the combined filtrate and washings were evaporated to about-150 ml. The addition of 2 N HCl dissolves the 2,4-diamino product, which was then precipitated by the addition of sodium hyroxide. It was recrystallized from 95% alcohol,-yielding 500 mg. of 2.4-diamino-5-methylpyrido(2,3-d)py1imidine with a melting point of 320.

Example 3.--r2,4rdfamin0;56ietramethylenepyriclo (2,3-d)pyrimidine Twenty-four grams of 2,4.6-triaminopyrimidine was heated with 70 g. of cyclohexanone Z-ethylcarboxylate in an oil bath at 220-240 for minutes. During this time the low-boiling fraction distilled off, after which the-reacder reflux conditions for 30 minutes with 180 m1. of phosuphorus oxychloride.

The clear solution-was evaporated to small volume and poured over ice. The solution was neutralized with ammonium hydroxideaud filtered. The moistcake .was-treatedwith 300 ml. of .2 N NaSI-I and heated overnightina steel bomb at 140. yellow precipitate was collected and dissolved in dilute sodium. hydroxide and reprecipitated by the addition of acetic acid.

The resulting Two grams of the above 7-mercapto compound was refluxed in 250 m1. of 95% alcohol and ml. of ammonium .hydroxide with 5 g. of Raney nickel. After three hours, ,anotherportion of 50ml. ammonium hydroxide and 5 g.

of Raney nickel catalyst was added and refluxed for'an- Example 4.-2,4-diamino-5-propylpyrido(2,3-d)

v pyrimidine "Thirty grams of 2,4,6-triaminopyrimidine was heated in an oil bath at 230 -240 with 100-g. .ofethyl butyrylacetate other 12 hours; The solution-was filtered and the Raney for 30 minutes during which time the low-boiling fraction was distilled off. The reaction mixture was treated as-in Example 1 and the subsequent steps carried out in the same way as in Example 1, except the mixture of chloro derivative and sodium hydrosulfi de was heated at 155 for 12 hours. The product was characterized by its ultraviolet absorption spectrum: pH 1, 270 my; 312mg; 345-360mp. (inflection) and pH' 11,265 mu (inflection), 338 11111..

Example 5 .2,4.-diamin0-5-methyl-6-burylpyrid0(2,3-d pyrimidine Thirty grams of 2,4,6-triaminopyrimidine was treated with 100 g. of ethyl-a-butylacetoacetate as in Example 1.

The residue was treated with 1000 nil. .ofacetic acid and 100 ml. of aceticanhydrideunder reflux conditions as in Example 1, and the acetylated 2,4-diamino-6-butyl-7- hydroxy-S-methylpyrido(2,3-d)pyrimidine boiled under reflux conditions with 350 ml. of phosphorus oxychloride. The-reaction mixture was worked up as in Example 1.

The wet cake then was heated in a steel bomb at 155 overnight with 600 ml. of 2 N NaSI-Ipsolution. The resulting precipitate was dissolved in 650 ml. of l N sodium hydroxide. by warming, and the clear solution was acidified with acetic acid. Ten grams of 2,4-diamino-6-butyl 5- methyl-7-mercaptopyrido(2,3-d)pyrimidine was boiled under reflux conditions with vigorous agitation in the'presence of 10 g. of potassiumcarbonate in 1 liter of water and 30 g. Raney nickel catalyst for 4 hours. Another 30 g. of Raney nickel was added and boiled for another 2 hours to complete the reaction. The product was isolated as in Example 1 and was recrystallized from alcohol. Ultraviolet absorption spectrum 7\ max.=275 .mn,'325 m and 3551'1'1M (inflection) at pH 1 and 260-270 III/A (inflection) and'338 III/L at pH 11.

Example 6.2,4-diamino5,6-trimethylenepyrido (2,3-,d V pyrimidine Twenty-five grams of 2,4,6-triaminopyrimidine was treated with 75 g. of cyclopentanone Z-ethylcarboxylate-as in Example 1.

Ten grams of the product was acetylated, in ml. acetic anhydride and 1 liter of acetic acid. After evaporating the solvent the residue'was treated with 250 ml. phosphorus oxychloride in a reflux condition and the isolated crude 2,4-diarnino-5,6-trimethylene-7-chloropyrido(2,3-d)pyrimidine was reacted with 2 N NaSH as in Example 1, except that thereaction was carried out at a temperature of Four grams of 2,4-diamino-5,6- trimethylene-7-mercaptopyrido(2,3-d)pyrimidine was reacted with 10 g. of Raney nickel catalyst in 500 ml. of 95% alcohol in the presence of 5 0 ml. of ammonium hydroxide. The crude 2,4-diamino-5,6-tri1nethylenepyrido(2,3-d)pyrimidine was recrystallized from 95% alcohol.

Ultraviolet absorption spectrum: pH 1, 321-322 mp. and 350-370 mp. (inflection); pH 11, 260-270 mp. (inflection) and 345 m,u.

What we claim is: Y

1. A 2,4-diaminopyrido(2,3-d)pyrimidine of the formula of lower alkyl radicals and together are selected from the group consisting of the divalent trimethylcneand tetramethylene radicals.

2. 2,4 diamino-S-methyl-fi-butylpyrido(2,3 d)pyrimidine.

3. 2,4 diamino-S-methyl 6 propylpyrido-(2,3-d)pyrimidine. di 4. 2,4 diamino-5,6-trimethylenepyrido(2,3 d) pyrimine.

5 6 5. 2,4-diam1'no-5,6-tetramethylenepyrido(2,3 -d)pyrimi- OTHER REFERENCES Klisiecki et al.: Roczniki Chem, v01. 3, pp. 251-260 References Cited in the file of this patent 1 FOREIGN PATENTS 5 774,095 Great Britain May 8, 1957 

1. A 2,4-DIAMINOPYRIDO (2,3-D) PYRIMIDINE OF THE FORMULA 